C Exercise Example 21

100 cases of classic C language

Title: Monkey eating peach issues: the monkey off his first day of a number of peach, half eaten immediately, not addiction, but also eat a morning in turn eaten by the remaining peach half, then eat a . After the morning ate the day before the rest of the half a zero. Day 10 in the morning when you want to eat, see only one peach. Seeking first day of the total number picked.

Program analysis: take the method of reverse thinking, inferred from the forward.

1) Let x1 is the number of the previous day peaches, peaches for the next day set x2 number, then:

x2 = x1 / 2-1, x1 = (x2 + 1) * 2

x3 = x2 / 2-1, x2 = (x3 + 1) * 2

So: x = before (after x +1) * 2

2) From day 10 to day 1, by analogy, it is a cyclic process.

Source Code:

//  Created by www.w3big.com on 15/11/9.
//  Copyright © 2015年 本教程. All rights reserved.
//

#include <stdio.h>
#include <stdlib.h>
int main(){
    int day, x1 = 0, x2;
    day=9;
    x2=1;
    while(day>0) {
        x1=(x2+1)*2;  // 第一天的桃子数是第2天桃子数加1后的2倍
        x2=x1;
        day--;
    }
    printf("总数为 %d\n",x1);
    
    return 0;
}

The above example output is:

总数为 1534

100 cases of classic C language